Surgical drive units of surgical drive systems, for example, of systems of the kind mentioned at the outset, are normally cleansed, i.e., cleaned and optionally sterilized, after use during a surgical procedure carried out on a patient. A problem which occurs in drive units as a result of cleaning and sterilization is corrosion of contacts. It has, therefore, already been proposed that preferably electronically commutated direct-current motors that are not equipped with sensors be provided for surgical drive units. The sensors, for example, Hall-effect sensors, primarily serve, in particular, in the case of low rotational speeds, to determine a position of the rotor of the electric motor, in order to be able to optimally supply it with current.
Furthermore, it is known to use a pulse width modulation method to supply the total of M motor windings of the electric motor with current, M being a natural number, greater than or equal to two. A disadvantage of this is that the ideal current supply curve for each motor winding, namely a sinusoidal curve, can only be approximately achieved in practice. In particular, limits are reached due to limited clock frequencies of available processors for generating the pulse width modulation signals (PWM signals).
An object of the present invention is, therefore, to so improve a surgical motor control device, a surgical drive system and a method for controlling a surgical drive unit that a current supply curve is prescribable for the motor windings of the drive unit, which is as ideal as possible.